The angle bisectors of the three angles of XYZ, intersect at the incenter of the circle. With that incenter a circle can be drawn to touch the three sides internally. 6.
To comply with Navigation Rules and for distress signaling purposes all boats must carry a sound producing device (whistle, horn, siren, etc.) capable of a 4-second blast audible for Â½ mile. *Boats larger than 39.4 ft. are no longer required to have a bell (see Navigation Rules.)
History and development. The basic requirements of the field were to be able to produce a repeating sound, some way to attenuate the amplitude, a way to transmit the sound to the subject, and a means to record and interpret the subject's responses to the test.